This invention relates to current responsive, gas-actuated electrical connectors of the type embodied in a bushing plug for use in power distribution systems.
Electrical connectors wherein an arc is struck between relative movable electrodes and wherein the flow of an arc-extinguishing fluid or gas is caused by a plunger mechanism driven by the arc itself to extinguish the arc, are known and have been widely used in the art. These electrical connectors have the advantage that the power available for the plunger mechanism is therefore automatically increased with the current being handled. Such electrical connectors are exemplified in U.S. Pat. Nos. 1,955,215; 2,020,475; and, 3,542,986. More recently, these electrical connectors have been embodied in elbow and bushing plug configurations, as exemplified in U.S. Pat. No. 3,474,386, particularly for use in underground distribution systems.
While these electrical connectors have been satisfactory for their intended purpose, they are also complicated, complex, difficult to assemble and essentially impossible to disassemble, and are therefore expensive to manufacture. For example, once these more recent prior art current responsive, gas-actuated bushing plugs are assembled, a moving piston member assembly therein is permanently trapped within the confines of its cooperating cylinder and cannot be removed without destroying the bushing plug. Accordingly, the piston portion of the moving member assembly can neither be removed once the unit is in the field as, for example, for inspection or part replacement, nor even during the latter stages of the manufacturing process. Thus, when a single part of the piston assembly fails or becomes defective, from whatever cause, either during manufacture or in field operation, the entire bushing plug is essentially unusable and is therefore scrapped.
These and other disadvantages are overcome by the present invention wherein a bushing plug of the current responsive, gas-actuated type utilizing a movable piston assembly is provided. The entire bushing plug utilizes but a relatively small component count and is, moreover, structurally configured such that the moving piston assembly can readily be removed from the associated cylinder of the bushing plug, during manufacture and/or field operation. In a preferred embodiment, this is accomplished by utilizing a relatively small number of components which are threadedly engaged and removably fastened together to provide the overall bushing plug, thereby providing the attendant advantages of the prior art while avoiding the disadvantages thereof.